The Table of comparisons highlights a noticeable difference between the 3 methods of classifications. Column 1 (Seth) responds well to the question: "Where do those who belong to a particular category focus their energy, time and commitment for best effect and fulfillment?"
The Enneagram responds "less directly" to this question (in that the Enneagram may offer insight that one is a 'leader' but not where to apply leadership for best effect or fulfillment).
Astrological categories provide little if any meaningful answers to this question.
Astrology and the Enneagram are not in the least "systems-orientated". They do not take account of the interactive dynamics of biological, ecological or social systems, such as that of one's local community, or how the global economy impacts and influences behaviours and attitudes. They do not therefore provide substantial insights into how we ought best interact with the world around us. They, in effect, offer little guidance as to where we might apply our energy and focus for best results and fulfillment.
The fields and disciplines of psychological testing, astrology, numerology and the Enneagram, are, like all fields of human understanding, based on certain beliefs about the nature of reality.
So when we seek to group people into meaningful categories it's prudent to first establish the belief-system by which those categorisations are made. If the belief-system is unduly limited, individuals and groups will necessarily be categorised or 'squeezed' into various psychological or astrological 'boxes' to fit the observed behaviours. In the process those capabilities and potentials that lay beyond the accepted framework of belief - which could otherwise be recognised and developed for personal and social benefit -- will be ignored or denied.